Mungo Park’s second expedition in 1805-1806 was a deadly failure, yet it did nothing to diminish his posthumous reputation as a national hero. What prompted this expedition, why it failed, and how it inspired new expeditions in the aftermath of the Napoleonic Wars are the subjects of this chapter. It frames Park’s expedition in the context of the transatlantic slave trade, showing how that trade shaped British imperial rivalry with France and Park’s efforts to solve the riddle of the Niger River’s route and outlet. Logistical problems, political tensions, and endemic diseases weakened the expeditionary force, and violent clashes with Africans along the Niger led to the deaths of Park and his remaining companions at Bussa. An investigation by the African trader Isaaco confirmed Park’s fate. With the end of the Napoleonic Wars, the British developed an ambitious new plan to vindicate Park’s sacrifice by sending expeditions to the Niger and the Congo.